Page 273 - Handbook of Thermal Analysis of Construction Materials

Section 10.0 - Ready-Mix Concrete 253

In Fig. 24, calorimetric investigation shows the effect of the
stabilizer. [35] Normal cement (cell 1) shows an exothermal peak at about 10
hours. Cell 2 refers to the mix to which the stabilizer is added with the mix
water. The hydration is retarded and the peak shifts to 30–40 hours.
Addition of a stabilizer, 2 hours after the mix was prepared, shows that
hydration is almost stopped (cell 3). The sample in cell 4 was stabilized at
6 hours after the initial injection of mix water. The hydration is retarded for
about 24 hours. When the activator is added at 24 hours reaction was
initiated.

Figure 24. Conduction calorimetric curves of portland cement containing a stabilizer and
an activator.